Belt sander



March 28, 1961 T. BEDORTHA ETAL 2,976,652

BELT SANDER Filed July so, 1959 2 Sheets-Sheet 1 IN VEN TORS LAWRENCE 7. M00197 HA YL/0///V 1M HALL/WELL Filed July 30, 1959 March 28, 1961 T BEDORTHA ETAL 2,976,652

BELT SANDER 2 Sheets-Sheet 2 IN V EN TORS L Ail FENCE 77 5500197704 B?0// 14/. HAL L /WEL L BELT SANDER Lawrence T. Bedortha, Simsbury, and John W. Halliwell,

Windsor Locks, Conn, assignors to Halortha Engineermg Company, Inc, Hartford, (Iona, a corpora.- tion of Connecticut Filed July 30, 1959, Ser. No. 330,549

6 flaims. (Cl. 51-176) This invention relates to a sanding device and, more particularly, to a belt sander attachment for a portable power tool such as an electric drill.

It is the general object of the invention to provide a simple portable belt sanding device in the form of an attachment for a power hand tool and which, although particularly adapted for sanding curved convex surfaces, may easily be adapted for sanding flat surfaces.

The drawings show a preferred embodiment of the invention and such embodiment will be described, but it will be understood that various changes may be made from the construction disclosed, and that the drawings and description are not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawings:

Fig. l is a side view of the sanding attachment of this invention showing the same secured to a portable power drill for operation;

Fig. 2 is a front view of the sanding attachment;

Fig. 3 is a more detailed side view thereof;

Fig. 4 is another front view of the attachment showing it adapted to sand fiat surfaces;

Fig. 5 is an enlarged front view of a bracket utilized with the attachment to adapt it for flat surface sanding; and

Fig. 6 is a side view of the bracket shown in Fig. 5.

Referring now to the drawings in greater detail, it will be observed that the attachment of this invention has a generally Y-shaped frame comprising a post 10 and a fork 12. In all of the views, the post is shown as disposed vertically but the attachment can be used with the post disposed in other than in vertical position. In any event, the post should extend transversely or at a right angle to the axis of rotation of a chuck 14 for a power tool, such as a portable electric drill 16 to which the attachment is secured for operation.

Referring to the post more particularly and as best shown in Figs. 2 and 3, it will be seen that it is generally cylindrical but that the upper portion 18 thereof is provided with a flat surface facing away from the power tool chuck 14. This upper portion of the post 10 is provided with a suitable aperture to support an anti-friction bearing unit 20 which in turn rotatably supports a stub shaft 22. The shaft extends forwardly and rearwardly of the post 10, the rearwardly extending portion being received and gripped in the power tool chuck 14. A drive pulley 24 is secured to the extending front end portion of the shaft 22 and will be referred to hereinafter;

The bottom end portion 26 of the post 10 is of reduced diameter and is hollow, the bore thereof being provided to slidably receive the stem 28 of the fork 12. A coil spring 30 surrounds the telescoped portions of the post and fork to urge them in relative movement away from each other. While the base or bottom portion 26 of the post 10 has been shown hollow to receive the stem 28 of the fork 12, the stern could be made in larger Patented Mar. 28, 1961 ice proportions and hollow to receive the depending portion of the post. Therefore, the particular arrangement shown and described is not intended as a limitation on the invention, because any sliding engagement between the post and fork stem will suit the needs.

The fork 12 is bifurcated and the furcations 32, 32 thereof extend outwardly and downwardly. A pin 34 is threaded into the extending end of each furcation 32 to project forwardly therefrom, each pin 34 preferably being parallel with the shaft 22 of the drive pulley 24. A driven pulley 36 is rotatably mounted on the forwardly projecting portion of each pin 34 so that an endless abrasive belt B can be drawn over the drive pulley 24 and the two driven pulleys 36, 36. The said drive and driven pulleys are preferably made of Teflon, nylon, or a similar synthetic so as to reduce if not eliminate the need for lubrication.

The sanding belt or abrasive belt B can easily be applied manually to the attachment by compressing the coil spring 30. The belt is provided in' such length or diameter that after it is applied, the spring 30 will still be under some compression so as to apply tension to the belt. 1 Due to the belt tension, when the drive pulley 24 is rotated as by operation of the power drill 16, the belt will move in a generally triangular path over the drive pulley 24 and the pair of driven pulleys 36, 36. While it is not essential, it is preferred that means be provided to prevent inadvertent and undesirable rotation of the post 10 and fork 12 comprising the attachment frame with the chuck of the drill. Such means may comprise a length of wire 38 having a portion 40 which is bent to surround the body of the drill 16 and having an end portion 42 which is secured to the attachment frame post 10 as by a screw 44 or the like.

The attachment as thus far described can be used most conveniently to sand or abrade the convex curved surfaces of a workpiece such as the workpiece W shown in Fig. 2. That is, the convex surface of the workpiece W is engaged by that portion of the belt B traveling between the driven pulleys 36, 36 which are rotatable at the ends of the furcations of the fork 12. The said surface can be engaged with considerable force if desired and which will displace the belt B from its normal path to conform it to the surface being engaged. This will cause some compression of the coil spring 30 in movement of the fork 12 toward the post 10, i.e., in inward movement of the fork stem 28 in the bore of the hollow end 26 of the post. It should be understood that if inward movement of the fork relative to post is limited tension can be applied to the belt solely by the workpiece, thus eliminating need for the spring 30.

As best shown in Figs. 4, 5 and 6, the attachment can also be used to sand or otherwise abrade flat surfaces. That is, a bracket 46 is provided for attachment to the fork 12 and has a fiat bottom surface 48 which will be disposed adjacent to and parallel with the belt B between the driven pulleys 36, 36. The fork 12 is adapted to receive the bracket 46 by being provided with a tapped hole 50 extending into the end of its stern between the furcations 32, 32. Therefore, the bracket 46 is easily attached by a screw 52. As best seen in Fig. 5, the bracket 46 extends outwardly toward the driven pulleys 36, 36 and a roller 54 is rotatably secured at each extending end of the bracket to reduce friction in movement of the belt B across the bracket and to space it slightly from the flat surface 48 thereof.

When using the attachment to sand fiat surfaces, that portion of the belt B extending across the bracket 46 and between the driven pulleys 36, 36 engages the flat surface to be sanded or abraded. Considerable force can be applied in the abrading operation and, preferably, means are provided to prevent movement of the fork 12 toward the post 10 which would reduce tension on the belt during this operation. The means provided to prevent such belt slackening relative movement between the post and the fork comprises a pin 56 which is inserted in a suitable aperture in the reduced diameter portion 26 of the post 10 toprevent inward movement of the stem 28 of the fork 12. When not applied as shown in Fig. 4, the pin 56 can be inserted in an aperture 58 in the post 10 so that it will always be available for use as described. The aperture 58 in the post 10 does not intercept the bore in the post so that the pin when in serted therein will not limit inward movement of the stern 28 within the post bore.

The invention claimed is:

1. A belt sander attachment for an electric drill or other portable power tool of the type having a chuck, the said attachment comprising a vertical post having an extending bottom end, a shaft rotatably supported in the post and projecting forwardly and rearwardly therefrom with its rearwardly projecting end adapted to be gripped in a chuck, a drive pulley secured to the forwardly projecting end of the shaft, a bifurcated fork having its stem slidably engaged with the bottom end of the post for relative movement therebetween, and a pair of driven pulleys respectively rotatably mounted on the ends of the furcations of the fork so as to receive an abrasive belt driven by the .drive pulley whereby the attachment is adapted to sand a convex surface engaging the belt between the driven pulleys and displacing it to apply tension to the belt.

2. A belt sander attachment as set forth in claim 1 and wherein means is provided to connect the attachment to the power tool other than by the chuck to overcome any tendency of the attachment to rotate with the chuck.

3. A belt sander attachment for an electric drill or other portable power tool of the type having a chuck, the said attachment comprising a vertical post having an extending bottom end, a shaft rotatably supported in the post and projecting forwardly and rearwardly therefrom with its rearwardly projecting end adapted to be gripped in a chuck, a drive pulley secured to the forwardly projecting end of the shaft, 21 bifurcated fork having its stem slidably engaged with the bottom end of the post for relative movement therebetween, a pair of driven pulleys respectively rotatably mounted on the ends of the furcations of the fork so as to receive an abrasive belt driven by the drive pulley, and spring means disposed between the post and the fork to apply tension to the belt, whereby the attachment is adapted to sand a convex surface by engaging it between the driven pulleys.

4. A belt sander attachment as set forth in claim 3 and wherein means is provided to connect the attachment to the power tool other than by the chuck to overcome any tendency of the attachment to rotate with the chuck.

5. A belt sander attachment for an electric drill or other portable power tool of the type having a chuck, the said attachment comprising a vertical post having an extending bottom end, a shaft rotatably supported in the post and projecting forwardly and rearwardly therefrom with its rearwardly projecting end adapted to be gripped in a chuck, a drive pulley secured to the forwardly projecting end of the shaft, a bifurcated fork having its stem slidably engaged with the bottom end of the post for relative movement therebetween, a pair of driven pulleys respectively rotatably mounted on the ends of the furcations of the fork so as to receive an abrasive belt driven by the drive pulley, spring means disposed between the post and the fork to apply tension to the belt, a bracket detachably secured to the fork between the furcations and having a fiat surface disposed between the driven pulleys and adjacent the belt, and means limiting movement of the fork toward the post to adapt the attachment to sand flat surface workpieces between the driven pulleys, the last mentioned means and the bracket being detachably connected to the attachment for removal to adapt the attachment to sand a convex surface by engaging it between the driven pulleys.

6. A belt sander attachment as set forth in claim 5 and wherein means is provided to connect the attachment to the power tool other than by the chuck to overcome any tendency of the attachment to rotate with the chuck.

References Cited in the file of this patent UNITED STATES PATENTS 1,717,995 Moore June 18, 1929 2,301,853 Cannon Nov. 10, 1942 2,401,670 Spetz June 4, 1946 2,483,720 Asbury Oct. 4, 1949 2,538,044 Ruehle Ian. 16, 1951 2,560,102 Guinn July 10, 1951 2,647,350 Blazek Aug. 4, 1953 

